1. Field of the Invention
This invention relates to a beverage brewer and method of brewing and more particularly to a hot beverage brewer with a brew tubular brew valve and method of making a hot beverage using such a tubular brew valve.
2. Discussion of the Prior Art
In U.S. Pat. No. 5,000,082 issued Mar. 19, 1991, to Lassota for “Beverage Maker and Method of Making Beverage” a coffee brewer is disclosed in which a dispenser valve assembly is in the form of a tube assembly with an inlet opening that is selectively moved between an open position in which the inlet opening is beneath a preselected water level and a closed position in which the inlet opening is above the preselected water level. This is a large commercial brewer with gallons of coffee being brewed into large, insulated dispensing urns that have serving faucets and are generally removed from the brewer after being filled to enable another empty urn to take its place.
One significant advantage of the use of an open tube assembly for the dispense tube is that when the tube assembly is in the closed position, the tube assembly is drained and cleaned by the steam of any residual water to avoid the formation of mineral and lime deposits that change the effective diameter and thereby undesirably alter the flow rate through the dispense tube assembly. Such lime deposits when formed in a conventional sliding door solenoid controlled valve can also interfere with closing of the valve. For these reasons, it is advantageous to use a dispense tube assembly instead of a conventional solenoid controlled valve that closes off the water tank.
The dispense tube assembly is mounted at an angle to the side of the water tank, and the water is conveyed laterally and downwardly by the tube assembly to an outlet end. The outlet end feeds a laterally displaced brew head that is fixedly mounted at a location spaced laterally from the side of the water tank. It has been determined by the inventors that it is important to make sure that the inlet end, when raised to the closed position, is substantially above the preselected water level in the tank to make sure that no water enters the inlet end due to splashing or the like. Similarly, it has been determined that it is important to make sure that the inlet tube is substantially beneath the preselected surface level of the water to make sure that it is in fact beneath the actual surface of the water and to reduce turbulence that would occur if the inlet end is at the surface level or only slightly beneath the surface. Disadvantageously, because of the angular movement of the tube assembly a greater amount of travel of the tube is needed to achieve a given amount of change in vertical position relative to the preselected level of the water in the tank than would be required if the movement were in a vertical direction perpendicular to the preselected surface level.
The raising and lowering of the inlet opening of the tube is achieved by sliding movement of an inlet tube within a stationary outlet tube fixedly located outlet end located outside of the water tank and above the brew basket. A coil spring connected to a spring retainer biases the movable tube toward the open position with the effective length of the tube assembly fully extended to maximum length. An electromechanical drive apparatus such as a solenoid, motor or other electronic apparatus is described as being also externally mechanically linked to the spring retainer and used to move the movably mounted portion of the tube assembly to the open position against resistance by the coil spring. In the only operation described in the patent, once the tube assembly is opened for dispensing hot water into the brew basket it remains open for the entire dispense period and thus there was no excessive operation of the drive apparatus during a given brew cycle. The drive apparatus is energized only once at the start of the dispense period and then de-energized at the end of the dispense period. Thus, there is little concern about the mechanical drive being used to move the dispense tube between the open and closed positions.
In U.S. Pat. No. 6,148,717 issued Nov. 21, 2000, to Lassota for “Beverage Maker with Intermittent Beverage Liquid Dispenser and Apparatus and Method for Uniform Contact of Brew Ingredient with Brew”, a hot beverage maker is disclosed in which a conventional, non-tubular, solenoid controlled valve is used to dispense hot water from a hot water tank to the brew basket. As taught in that patent, there are advantages to providing the hot water to the brew basket on an intermittent basis throughout the dispense period rather than continuously during the dispense period. While use of a conventional solenoid-controlled valve enables successful operation it does not provide the advantages of a tubular dispense valve as discussed above and shown in the above U.S. Pat. No. 5,000,082. While the tubular dispense assembly is well adapted for use in a system in which the valve remains open throughout the dispense period, there are some disadvantages of wear and configuration awkwardness generally because of the side mounting, the sliding of one tube within another and the external mechanical drive linkage. The side mounting requires the spray head and the outlet of the tube to be spaced laterally from the water tank, and the use of two sliding tubes requires the use of seals that in time wear and may leak.